Process and apparatus for stretch spinning cuprammonium rayon



Aug. 21, 1962 HIIZU AIZAWA ETAL 3,049,755

PROCESS AND APPARATUS FOR STRETCH smmmc CUPRAMMONIUM RAYON Filed July25, 1960 2 Sheets-Sheet l PRIOR ART INVENTOR.

BY W TM Aug. 21, 1962 HHZU AIZAWA ETA]. 3,049,755

' PROCESS AND APPARATUS FOR STRETCH SPINNING CUPRAMMONIUM RAYON FiledJuly 25, 1960 2 Sheets-Sheet 2 wm uifw *M ii -7s.

United States Patent 7, 3,049,755 Patented Aug. 21, 1962 3,049,755PROCESS AND APPARATUS FOR STRETCH SPIN- NING CUPRAMMONIUM RAYON HiizuAizawa, Nobeoka-shi, and Fuknsa Ishida, Hyugashi, Japan, assignors toAsahi Kasei Kogyo Kabushiki Kaisha, Osaka, Japan, a corporation of JapanFiled July 25, 1960, Ser. No. 45,051 Claims priority, application JapanAug. 3, 1959 3 Claims. (Cl. 18-8) This invention relates to astretch-spinning process of cuprammonium rayon and more particularly toan improved method for manufacturing cuprammonium filament yarn bydischarging thread forming. material in liquid form spinning solutioninto a stream of coagulating liquid flow.

An object of the present invention is to provide a method for producingcuprammonium rayon which is superior in both tenacity and elongation,particularly in the latter.

Another object of the present invention is to provide a method forproducing cuprammonium rayon having homogeneous sectional structure andeasy resin finishing character.

The other objects will appear from the following description of anillustrative embodiment of the invention taken together with theaccompanying drawings.

FIGURE 1 of the accompanying drawings is a sectional view of anapparatus for producing rayon filament yarn suitable for carrying outthe present invention.

FIGURE 2 shows the relation of filament diameter 1) and path distancefrom spinneret (cm.), a solid line representing the aforesaid relationaccording to the present invention and a dotted line representing thesame according to a conventional process.

FIGURE 3 shows a typical conventional funnel type apparatus.

In the art as hitherto practised, a ouprammonium spinning solution isconventionally discharged into a rapidly flowing stream coagulatingliquid and stretched or drawn due to the flow of the stream while beingof partially coagulated form, and the partial coagulate is then furtherstretched or drawn in the rapid water stream due to drawing from theoutside. The last stretching or drawing is efiected when and after thespinning solution was substantially coagulated, with the result ofincreasing tenacity of the final thread but reducing elongation. Such afinal thread is so brittle that it is not suitable for resin finishing.This is a major drawback of conventionally produced cuprammonium rayonthreads.

According to the present invention, a cuprammonium spinning solution isdischarged into a coagulating liquid funnel, and stretched or drawn,immediately after the discharging and while the spinning solution is notyet completely coagulated, but still in suitable state (5X10 25 X poise)for strong stretching, by rapid flow of the coagulating liquid whereuponthe spinning water is suddenly led into an expanded path thereby greatlyreducing the rate of motion of the filament which is formed bycoagulation of the spinning solution. In the expanded path, coagulationof the filament is completed due to turbulent diffusion of ammonia whilethe filament is loose or relaxed, whereafter the completely coagulatedfilament is drawn out by an external drawing. A main difference betweenthe .prior art and the process according to the invention consists inthat, after substantial coagulation has been attained, the filamentremains for a time, until coagulation is complete, in a slowly flowingstream of coagulating water and is not subjected to further drawingwould be the case in the conventional process.

The present invention shall now be described in more detail, havingreference to the accompanying drawings. In FIG. 1, reference numeral 6designates spinneret mounting means, 4 is a spinneret, and 1 is aconical tube located below and distanced from the spinneret 4 to providesufficient space for introducing coagulating liquid. Spinning solution ifed from an upper feed pipe 5 to means 6 and is discharged through anumber of fine holes into the spinning water. The coagulating liquid isfed from an upper inlet 7, and flows into conical tube 1 together withthe .spinning solution. The spinning solution and the coagulating liquidflow downward passing through a conical tube zone and on through astraight long tube 2 of smaller diameter, wherein the spinning solutionis not yet completely coagulated but sufiiciently so that it can bedrawn to its maximum possible length by the torrent of the coagulatingliquid and that it can be drawn out of tube 2 by the pull applied fromthe outside reeling or winding device, reference numeral 3 designates acoagulation tube such as an expanded straight tube the diameter of whichis greater than that of tube 2, and the lower end of the tube 2 isinserted into the closed upper end of tube 3. The torrent of thecoagulating liquid in tube 2 enters suddenly the coagulation tube 3whereby its flowing speed is suddenly and greatly reduced. The filamentdrawn to the utmost extent is loosed or relaxed and is completelycoagulated. The filament in tube 3 is taken up by the aforesaid drawingapplied from the outside reeling or winding device without beingsubjected to further stretching. In the preferred embodiment of theapparatus, the ratio of the diameter of tube 2 to the diameter at .theupper end of conical tube 1 is d ad /2 to A, and the length of conicaltube 1, l and the length of straight tube 2, may be 4-20 cm. and 3-25cm. respectively when d is 1.5-3.0 cm. and d i 0.5-1.0 cm. and thediameter of tube 3, d is also preferable to be 1.2-4 times d As will beclear from FIGURE 2, the diameter of the thread is reduced greatly untilthe point where the spinning solution leaves the lower end of tube 2 andthen it is slowly reduced in tube 3 while releasing ammonia, wherebydestruction of the cross sectional area of thread is prevented and thethread is provided with uniform sectional structure. In contrastthereto, according to conventional processes, the thread is drawn evenin tube 3, whereby the thread is subjected to severe deformation and isgiven a heterogeneous sectional structure.

The following examples will serve to understand the present invention,given a comparison wn'h a case wherein conventional funnels are used.The spinning solution contained 10% by weight of cellulose, 7.3% byweight of ammonia and 3.65% by weight of copper.

I. SKEIN SPINNING Conical tube Straight long Coagu- Elonga- Elongatubelating Titer, Tenacity tion, Tenacity tron, No. tube denier Dry, Dry,wet, Wet,

d (cm) gr./den. percent gr./den. percent 11 (0111) (11 (cm) 12 (0111) dz(cm) 1 An apparatus shown in FIGURE 3 was used.

II. CONTINUOUS SPINNING Conical tube Straight long Coagutube latingTenacity Elonga- Tenacity Elonga- No. tube Titer, Dry, tion, wet, on, d;(em) denier gr./den. Dry, gr./den. Wet, Z1 (cm) di (cm) I: (cm) (11 (cm)percent percent 1 An apparatus shown in FIGURE 3 was used.

Dotted and solid lines in FIGURE 2 correspond respectively to Nos. -1and 3 of the above table I.

coagulated and stretched filament is discharged from said opening at thelower end of said third tube means.

III. FILAMENT YARN (40 DEN) RESIN FINISHED Conventional filament Presentfilament Resin conc., percent in bath 8 12 16 20 8 12 16 20 Resin,percent attached 3.4 4.5 5.4 6.5 3.8 4.6 5.6 6.8 Tenacity:

Dry, g 79.0 89.4 90.0 90.2 85.6 98.6 112.0 110.8 119.5 124.6

Wet, g 47.6 55.4 58.6 62.2 65.8 65.8 72.0 73.8 78.6 86.8 Elongation:

Dry, percent 12.0 10.0 10.0 8.0 7.4 13.2 10.5 11.1 9.2 9.9

Wet, percent 19.3 16.8 15.5 15.0 13.8 20.0 18.0 17.9 16.7 15.0

We claim: 2. A process for stretch-spinning of cuprammonium 1. In anapparatus for the stretch spinning of cuprama hi h comprises moniumrayon, in combination, a first, descending co- 55 agulating andstretching tube means having an upper end (a) eXtruding a cuprammoniumspinning solution siadapted for introduction thereinto of cuprammoniummultaneously with a coagulating liquid into a stretch spinning8011111011 and a stream Of coagulating liquid, fOl' coagulation zonehaving an intermediate region simultaneous flow through said tube meansin the same wherein the diameter of said zone transverse to thedirection, said first tube means in the upp r part thereof direction offlow of said solution and liquid is subhaving a diameter al and a lengthand being tapered stantially narrowed, whereby the flow velocity of saidin the remaining lower part toward the lower end thereof coagulatingliquid in the remaining part of said zone, which has a narr diameter 2;a sficolld, descefldiPg subsequent to said narrowed region, is madegreater waglllafing and Stretching lube means connected Wlth than theflow velocity of the coagulate being for-med upper end to tbs of saidfirst tube-means, Sald by the contact of said cuprammonium solution withsficond mefms havmg a length 12 bemg substan' said coagulating liquid,and said coagulate is thereby tlally of said diameter d throughout saidlength 1 and being Stretched and a third coagulating tube means havingan enclosed upper end into which the lower end of said second tube meanspaismg said coagillatlflg hquld and coagillate there opensnnrestrictedly and a further opening at the lower f the Same of to end,said third tube means having a substantially con- Pletlon of thecoagulatlon, unrestnctedly mm a stant diameter d 1 :1 ranging from (4 to20) :(3 to 25); ther coagulation zone wherein the flow rate of the l :dranging from 4:1.5 to 20:3.0; l zd ranging from coagulating liquid isSuddenly diminished, thfimby 310.5 to 25:10; d zd ranging from 2: 1 to4:1, and d permitting completion of the coagulation of the cobeingsubstantially larger than d whereby completely agulate while the latteris in a relaxed state.

3. A process for stretch-spinning of cupramrnonium rayon, whichcomprises (a) extruding a cuprammonium spinning solution simultaneouslywith a coagulating liquid into a stretch coagulation zone having anintermediate region wherein the diameter of said zone transverse to thedirection of flow of said solution and liquid is substantially narrowed,whereby the flow velocity of said coagulating liquid in the remainingpart of said zone, subsequent to said narrowed region, is made greaterthan the flow velocity of the coagulate being formed being stretchedwhen said coagulate has a viscosity of about 5000 to 25,000 poises, and

(b) passing said coagulating liquid and coagulate therein, with the samedirection of flow and prior to completion of the coagulation,unrestrictedly into a further coagulation zone wherein the fiow rate ofthe coagulating liquid is suddenly diminished, thereby permittingcompletion of the coagulation of the coagulate while the latter is in arelaxed state.

References Cited in the file of this patent UNITED STATES PATENTS by thecontact of said cuprammonium solution with said coagulating liquid, andsaid coagulate is thereby

